The present invention relates to a laminator for laminating a film on a substrate.
There has been known a laminator using a pair of pressure rolls for laminating a film on one or both of opposite surfaces of a substrate. When a substrate which has been transferred toward the laminator is supplied to an area between the pressure rolls, a film is also supplied to the area between the pressure rolls, to thereby adhere the film to the substrate under pressure.
Pressure required for adhering the film to the substrate is applied by a pressure-applying apparatus such as an air cylinder apparatus, which applies force to bearings provided at opposite end portions of the pressure rolls.
FIG. 9 shows a set of diagrams for explaining an effect of bending of pressure rolls, which occurs when force is applied to bearings on the pressure rolls by a pressure-applying apparatus. In FIG. 9(a), force is directly applied, by pressure-applying apparatuses provided at positions A, to bearings 3 on opposite ends of a pair of pressure rolls having a substrate 1 sandwiched therebetween, or force is applied, by pressure-applying apparatuses provided at positions B. to the bearings 3 through levers 4 extending outward in an axial direction of the pressure rolls 2. In either case, the pressure rolls 2 having the substrate 1 sandwiched therebetween are bent due to a bending moment, which causes the pressure rolls to be recessed away from each other as shown in FIG. 9(b). Consequently, the pressure of the pressure rolls 2 becomes lower at a central portion of the substrate 1 and therefore, the film cannot be laminated on the substrate 1 under uniform pressure.
For laminating, for example, a photosensitive resist film on a substrate for a print circuit board substrate, it is strongly desired to adhere the film to the substrate under uniform pressure.
Therefore, a proposal has been made to extend the levers 4 inward in the axial direction of the pressure rolls 2 and apply force to the bearings 3 through the levers 4, by means of pressure-applying apparatuses provided at positions C axially inward of the bearings 3 (reference is made to Unexamined Japanese Patent Application Public Disclosure No. 10-146891). In this arrangement, the pair of pressure rolls 2 tend to be recessed away from each other as shown in FIG. 9(b), due to a bending moment generated depending on lateral loads acting on the bearings 3. On the other hand, the pressure rolls tend to be projected toward each other as shown in FIG. 9(d), due to a bending moment generated at the bearings 3 depending on the force acting on inner end portions of the levers 4 and the lengths of arms of the levers 4. These tendencies of bending in opposite directions are substantially canceled. Consequently, as shown in FIG. 9(e), the pressure rolls 2 can be held in a substantially straight condition to apply pressure to the substrate 1 and the film. The same effect as obtained in the case of FIG. 9(c) can also be obtained by applying force to the inner end portions of the levers 4 through bars 5, as shown in FIG. 9(f). The arrangement shown in FIG. 9(f) is advantageous in that pressure-applying apparatuses can be provided at outward positions B which have more space.
Based on this idea disclosed in Unexamined Japanese Patent Application Public Disclosure No. 10-146891, the present invention provides a specific arrangement for applying uniform pressure to a substrate and a film by means of a pair of pressure rolls.
For providing a specific arrangement, it is preferred that the following conditions be met:
(1) bearings provided at opposite end portions of the pressure rolls are capable of enabling smooth rotation of the pressure rolls and withstanding a large bending moment generated in the pressure rolls;
(2) the bearings are capable of maintaining their function even when imparted with a rotational motion due to the above-mentioned bending moment;
(3) the pressure rolls are substantially prevented from moving in an axial direction thereof and a direction perpendicular to the axial direction (a direction of travel of the substrate);
(4) a position at which force is applied to an end portion of a lever extending axially inward of the bearing is variable;
(5) the pressure roll associated with a pressure-applying apparatus is capable of moving toward and away from the pressure roll on the opposite side thereof in parallel relation;
(6) attachment and detachment of the pressure roll is easily conducted; and
(7) the pair of pressure rolls are the same in terms of a mechanism comprising the pressure roll and the bearing associated therewith so that the pressure rolls are subject to the same deformation when force and a bending moment are applied to the pressure rolls by the pressure-applying apparatus.
In order to meet at least some of these conditions, the present invention provides a laminator for laminating a film on a substrate, comprising:
a pair of pressure rolls adapted to have the substrate and the film sandwiched therebetween;
bearings adapted to rotatably support end portions of each of the pressure rolls, each of the bearings comprising a bearing housing;
a lever having one end attached to the bearing housing and the other end located inward of the bearing in an axial direction of the pressure roll; and
a pressure-applying apparatus for applying force to the other end of the lever, to thereby apply pressure through the bearing to the substrate and the film between the pair of pressure rolls, and generate bending moment which tends to cause the pair of pressure rolls to be projected toward each other, wherein the laminator further comprises:
a shaft for supporting the bearings, the shaft being disposed in spaced parallel relation to the pressure roll; and
extension arms formed in the bearing housings and connected to the shaft so that the bearing housings are capable of pivotal movement about the axis of the shaft and also capable of pivotal movement about an axis perpendicular to the axis of the shaft.
The bearing housings may be connected to the shaft through bearings having spherical seats.
Opposite end portions of the shaft may be rotatably supported on side plates through rolling bearings, and
a synchronization mechanism may be provided between the shaft and the extension arms connected thereto for restraining relative rotation between the shaft and the extension arms so as to synchronize movements of the bearing housings on opposite ends of the pressure roll during pivotal movement of the bearing housings about the axis of the shaft.
The laminator may be arranged, such that:
a roller is provided on the other end of the lever;
a bar in contact with the roller and extending in the axial direction of the pressure roll is provided; and
the pressure-applying apparatus is provided outward of the bearing housing in the axial direction of the pressure roll and adapted to apply force to the roller on the other end of the lever in an indirect manner by applying force to the bar at a position in which the pressure-applying apparatus is provided.
A plurality of openings may be formed in the lever for receiving and supporting a shaft of the roller in a selective manner, the plurality of openings being arranged in the axial direction of the pressure roll, whereby a position of application of force to the roller can be changed by selecting one of the openings.
The laminator may be arranged, such that:
the bar has an I-shaped cross-section;
two levers extend from the bearing housing along opposite sides of a web portion of the I-shaped bar;
the roller provided on the other end of each of the two levers is located between two flange portions of the I-shaped bar on each of the opposite sides of the web portion of the I-shaped bar; and
the web portion of the I-shaped bar includes a slot formed therein for enabling a shaft connecting the two rollers provided on the opposite sides of the web portion to extend therethrough.
The laminator may be arranged, such that:
the bar comprises a hollow bar having a rectangular outer configuration, the hollow bar including a longitudinally extending opening formed in at least a side wall thereof facing the pressure roll;
the rollers are provided one on each of opposite sides of the other end of the lever, the other end of the lever extending from the opening to an inside of the hollow bar; and
the rollers are provided one on each of opposite sides of the opening inside the hollow bar.
The laminator may be arranged, such that:
the bearing housing comprises an outer first bearing housing element and an inner second bearing housing element;
the first bearing housing element comprises the extension arm and has a C-shaped opening for receiving the second bearing housing element;
the lever is attached to the first bearing housing element;
the second bearing housing element located on a side on which a drive mechanism for the pressure roll is provided comprises a plurality of rolling bearings for supporting an end shaft of the pressure roll, a gear provided axially outward of the rolling bearings and having a hollow shaft in which an outer end of the end shaft is fitted so that the hollow shaft and the outer end of the end shaft are rotatable as a single unit, and a plurality of rolling bearings for supporting the hollow shaft, the second bearing housing element being capable of being fixed in the C-shaped opening of the first bearing housing element; and
the second bearing housing element on a side thereof opposite to the side on which the drive mechanism is provided comprises a plurality of rolling bearings for supporting an end shaft of the pressure roll, and is capable of being fixed in the C-shaped opening of the first bearing housing element.
A holding member engageable with the bar may be provided in the lever or the bearing housing separately from the roller provided on the other end of the lever, so as to maintain a position of the bearing housing when the pressure roll is removed from the bearing housing.
The laminator may be arranged, such that:
the shaft for supporting the bearings is provided for each of the bearing housings;
each of the shafts has an outer end thereof supported on the side plate through a rolling bearing;
each of the shafts has an inner end thereof connected to an end portion of the extension arm;
a synchronizing rod is provided in spaced parallel relation to the shafts, the synchronizing rod having opposite ends thereof rotatably supported on the side plates through rolling bearings; and
the synchronizing rod and the end portions of the extension arms connected to the shafts are connected to each other through a link mechanism so that the bearing housings on opposite ends of the pressure roll move in synchronism with each other when the bearing housings pivotally move about the axes of the shafts.